Beamrider missile systems utilize a form of line of sight missile guidance in which a beam of spatially encoded electromagnetic radiation is projected in the direction of the target and a rearward-looking missile borne receiver decodes the spatial information and thereby determines the missile's position within the beam. The missile corrects its position as necessary to remain at or near the beam center until target impact.
The previously known forms of beamrider guidance have utilized spatial codes that are referenced to the beam projector and thus to the gunner's coordinate system. Such spatial codes are normally implemented with mechanical scan or nutation devices in the beam projector that produce this reference coordinate system for the missile receiver to decode. Transformation into missile coordinates prior to guidance command generation is then required unless the missile contains a roll stabilization system to minimize variation between projector and missile coordinate references.
It is the object of this invention to provide a spatial encoding technique that is totally independent of the beam projector roll orientation. This missile referenced spatial encoding method negates the need to either roll stabilize the missile, or to utilize a gyro for roll attitude measurement. This capability would be particularly desirable in lightweight, low cost, short range (350 to 750 meter maximum) missile systems. An inherent benefit of this invention, consistent with such system requirements, is the simple, no-moving-parts beam projector that is potentially a discardable item.